Hi Kate,
(I edited this response since I realized the process is even easier than what I originally posted.)
It's not a crazy question at all! In fact, this is a great technique to use, especially when building a map journal or series.
You can embed a story map (or any ArcGIS Online template app) in another story map. When you are adding a section or tab to your story map, choose "Web page" as your content type, then just paste in the URL of your other story map in the Webpage URL box.
The click Configure and choose "Stretch" so your story map will fill the entire main stage.
Here's a tip that you may want to use when embedding a story map: if you add "?&embed" to the end of your app URL (or just "&embed" if there is already a ? and other parameters in the URL) this will strip off the title and social media sharing icons from the embedded app. Since your main app already has these you probably don't need to duplicate them in one of your journal sections or series tabs. This tip works with most of the story map apps like swipe/spyglass, map tour, basic, etc. For example, click these two links to see the difference between standard and embedded mode in this Swipe story map.
http://story.maps.arcgis.com/apps/StorytellingSwipe/index.html?appid=97ae55e015774b7ea89fd0a52ca551c...
http://story.maps.arcgis.com/apps/StorytellingSwipe/index.html?appid=97ae55e015774b7ea89fd0a52ca551c...
To see an example of a story map within a story map check out this Map Series where you'll see a Map Journal in the "Point-of-Sale strategies" tab.
Hope this helps!
Owen
Owen Evans
Lead Product Engineer | StoryMaps